(I.) Field of The Invention
The present invention relates to the field of orthopedic surgery and, more particularly, to a method and apparatus for bone fracture reduction and fixation.
(II.) Prior Art
Existing techniques for fracture reduction and fixation in cases requiring artificial fixation of a bone fragment involve extensive surgical procedures. Typically, a large incision in the vicinity of the fracture is necessary to expose the fracture and facilitate location of the bone fragment. The fragment is then mechanically reattached to the bone from which it was broken away by means of fasteners, for example, plates and screws. Such surgery is a lengthy procedure, generally 1-3 hours, subjecting the patient to the inherent hazards and discomfort of such procedures. The size of the incision generally requires the use of a tourniquet to control bleeding during surgery. Furthermore, extensive soft tissue stripping is frequently necessitated which creates a substantial risk of infection and non-union of the fracture.
Existing non-surgical techniques for fracture immobilization and partial reduction employ a frame-like apparatus with extended screws mounted thereto for attachment to the fracture. This apparatus, or frame, is constructed of various standard components to achieve the particular configuration required by the geometry of the frame to be immobilized. These components include sections of round tubing of various lengths. Interconnection of the lengths of tubing and attachment of other components is facilitated by blocks which clamp to the external surface of the tubing. These blocks consist of a body and a clevis. They are drilled with a hole slightly larger in diameter than the diameter of the tube. The body of the block has two threaded studs perpendicular to the axis of the hole extending from opposite faces of the body. A locknut placed over one of these studs engages the face of the clevis, thereby clamping the block to the length of tubing. Other components are then attached to the other stud.
One such component is a tie bar which permits the attachment of one length of tubing to another. Another component is a clamp which engages a cylindrical stainless steel pin. The pin is threaded at one end in the manner of a common wood screw. Such pins are screwed into holes which are drilled into the main segment of the fractured bone and into one or more bone fragments. The pins, the clamps and the blocks can be freely positioned with respect to one another and with respect to the tubular frame. Pins attached to the bone and bone fragments may be manipulated to any desired position and then rigidly secured to the frame members, thereby immobilizing the fracture and positioning the bone and bone fragment for healing. The device is then maintained in position for several weeks until the bone is, at least, partially heeled. Eventually, the prior art device is removed and more conventional fixation devices, such as a cast, are used to complete the therapeutic treatment.
Partial reduction may be accomplished by positioning the pins on the frame so as to reposition the bone fragments relative to the bone. However, such partial reduction cannot be accurately controlled. Thus, such prior art external fixators are not useful for reduction of fractures requiring significant accuracy, such as articular fractures. Furthermore, the external fixator utilizes no application of internal fixation. The patient is thus confined by the apparatus for an extended period of time (as long as several weeks) as healing proceeds.